Electronic social networks are network-based services that provide users with an ability to associate and communicate with each other. Users are able to identify other users with whom they have a social relationship (e.g., establishing other users as contacts within a social networking service). Once a social relationship has been expressed, the users typically are able to see communications, status updates, and other notifications generated by the social networking activities of their contacts.
Social networks also provide services that enable users to identify and associate with groups of other users who share a common interest. Some groups are manually created by a user, and other users are then able to choose to associate themselves with the group. In some cases, membership is open where any user is granted membership in the group upon request. In other cases, membership is moderated where one or more users manually decide to accept or deny other users' requests for membership.